A trailer and a towing vehicle are two relatively independent entities that are interconnected by a hitching device. The trailer and the vehicle each have their own center of gravity, and when in motion each is subjected to its own pitch, yaw, and roll motions. Because of these differing motions by the trailer and towing vehicle, the interconnection between them is subjected to numerous intermittent jerking forces in addition to the motivational force exerted by the towing vehicle on the trailer. These unsteady, irregular and rapidly changing jerking forces are very undesirable. They cause annoyance and discomfort to drivers and their passengers. They place further burdens on the suspension systems of the trailer such that the contents of the trailer can be jostled and damaged. They cause wear and tear on every component of both the trailer and towing vehicle. It is clear that any attenuation of these jerking forces will result in a smoother and better ride which is safer for the occupants of the vehicle and also for the cargo in the trailer.
Prior art includes a multitude of systems for attenuating these jerking forces. Many of these systems are quite elaborate and require numerous springs and/or other shock absorbing devices. Thus, they can be prohibitively expensive. Other simpler systems dampen longitudinal surges but not vertical shocks. Still others dampen vertical shocks but not longitudinal surges.
Because of either the expense involved or a limitation on effectiveness, most of the hitches in use on the road today do not have any capacity to attenuate intermittent jerking motions and forces. An economical technique for attenuating a significant portion of these jerking motions and forces is clearly needed.